1. Field of the Invention
The present invention relates to a manufacturing method of a semiconductor device, and more particularly to a method of forming electrode wires on an insulating layer of the semiconductor device.
2. Description of the Background Art
In recent years, with micronization of semiconductor devices, a size of a connection hole formed in an insulating layer for electrical connection, between first and second conductive layers, is also micronized. The electrical connection is between a first conductive layer, which is a conductive diffused layer on a principal plane of a semiconductor substrate or a metal film on a semiconductor element, etc., and a second conductive layer, which is a metal film, etc. located on an upper side of the insulating layer.
With such a micronization of a connection hole, an aspect ratio of a connection hole (ratio of height to diameter of a connection hole) is increased. To meet this situation, an attempt has been proposed to achieve an electrical connection between the first conductive layer and second conductive layer, in which the second conductive layer is formed by sputtering and a space in the connection hole is closed by the second conductive layer and is then buried under an atmosphere of high temperature and high pressure.
For example, the Japanese Laid-Open Patent Publication (unexamined) Toku-Hyou-Hei 7-503106 discloses a manufacturing process of a semiconductor device including the steps of closing an upper part of a space in the internal part of a connection hole with a second conductive layer formed by sputtering while leaving the internal space, and burying the second conductive layer into the connection hole, whereby an electrical connection between the first conductive layer and the second conductive layer is achieved. This prior manufacturing process is hereinafter discussed more specifically with reference to FIG. 10 to FIG. 14.
First, as illustrated in FIG. 10, a first conductive layer 11 is formed on the upper part of a semiconductor element 10, an insulating layer 12 is further formed thereon, and a connection hole 13 is formed in the insulating layer 12.
Then, as illustrated in FIG. 11, a second conductive layer 14 is deposited by sputtering on the insulating layer 12 and in the internal part of the connection hole 13. At this time, as illustrated in FIG. 11, a thickness of the second conductive layer 14 deposited on the side wall 13a and on the bottom face 13b of the connection hole 13 is small as compared with that of the second conductive layer 14 coating the surface of the insulating layer 12. While continuing the deposition of the second conductive layer 14, a gap 15 of the second conductive layer 14 on the connection hole 13 is narrowed.
When further continuing the deposition of the second conductive layer 14 by sputtering, as illustrated in FIG. 12, the gap 15 of the second conductive layer on the connection hole 13 comes to be closed while a hollow space 16 being left in the internal part of the connection hole 13 comes to be closed while a hollow space 16 is left in the internal part of the connection hole 13.
Then, on maintaining the semiconductor device in an atmosphere of high pressure, the second conductive layer 14 is buried into the connection hole 13 until a state illustrated in FIG. 13 is achieved.
Further, as illustrated in FIG. 14, a conductive wire 17 is formed by etching the second conductive layer 14.
In the above-mentioned manufacturing process of a semiconductor device, the upper part of the hollow space 16 is closed with the second conductive layer 14 formed by sputtering while leaving the hollow space 16 in the internal part of the connection hole. Thereafter, the second conductive layer 14 is buried into the connection hole 13 by applying a high temperature and a high pressure, by which an electrical connection can be established between the first conductive layer 11 and the second conductive layer 14 through the connection hole 13.
However, in the mentioned manufacturing process of a semiconductor device, a problem exists in that etching is required to form the conductive wire 17 formed from the second conductor 14, and the conductive wire 17 formed by etching may be defective and is of a low yield.